A DC to DC converter converts an input DC voltage to an output DC voltage for one or more particular loads. The DC to DC converter may have differing characteristics depending on many factors including the type of load. Many loads require a fixed output DC voltage level. However, other loads, e.g., a processor of a personal computer, may require differing output voltage levels in response to various conditions. To serve such loads, some DC to DC converters require precise startup voltage ramp rates, settling times, and perform “on-the-fly” output voltage changes. For instance, the DC to DC converter may provide a first DC output voltage to the processor during one time interval and then may provide a second DC output voltage to the processor during another time interval.
In order to effect such a change in output voltage of the DC to DC converter, a reference signal, Vp, provided to an error amplifier in a feedback path of a controller for the DC to DC converter may be changed. The error amplifier may compare the reference signal to a voltage level representative of the actual output voltage level, Vout, of the DC to DC converter in order to regulate a conductive state of at least one switch of the DC to DC converter to maintain the output voltage at a desired level despite changes in load condition.
However, in a conventional arrangement as the reference signal is changed, an excessive overshoot and undershoot of the output voltage from the desired output voltage may occur. For example, in one simulation for where the reference signal changed from 0.8 to 1.2 volts, an excessive overshoot of 74 millivolts occurred before the actual output voltage leveled off to the desired 1.2 volts.
Accordingly, there is a need to compensate for such changes in the reference voltage level to lessen the excessive overshoot and undershoot of the actual output voltage from the desired output voltage.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly.